package com.itheima.reggie.filter;

import com.alibaba.fastjson.JSON;
import com.itheima.reggie.common.BaseContext;
import com.itheima.reggie.common.R;
import lombok.extern.slf4j.Slf4j;
import org.springframework.util.AntPathMatcher;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * 登录页面优化
 *      当用户为登录时，对其访问进行拦截，并跳转到登录页面
 *
 *      配置类
 *          开启过滤器扫描
 *      过滤器
 *          设置过滤路径
 *          继承过滤器
 *          重写方法
 *              获取请求路径
 *              设置放行路径
 *              判断是否放行
 *                  放行，return
 *                  不放行，判断是否登录
 *                      登录，放行，return
 *                      未登录，返回指定"NOTLOGIN",code=0的json数据
 *                          前端根据数据进行判断，跳转到登录页
 */

@WebFilter(filterName = "LoginCheckFilter",urlPatterns = "/*")
@Slf4j
public class LoginCheckFilter implements Filter {

    public static final AntPathMatcher antPathMatcher = new AntPathMatcher();

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest)servletRequest;
        HttpServletResponse response = (HttpServletResponse)servletResponse;

        //1.获取本次请求的URI
        String uri = request.getRequestURI();
        log.info("请求uri：{}",uri);

        //2.判断本次请求, 是否需要登录, 才可以访问
        String[] uris = new String[]{
                "/employee/login",
                "/employee/logout",
                "/backend/**",
                "/front/**",
                "/common/**"
        };
        Boolean check = check(uri, uris);

        //存储当前修改者id
        BaseContext.setId((Long) request.getSession().getAttribute("employee"));

        //3.如果不需要，则直接放行
        if (check){
            log.info("请求放行：{}",uri);
            filterChain.doFilter(request,response);
            return;
        }

        //4.判断登录状态，如果已登录，则直接放行
        if (request.getSession().getAttribute("employee") != null){
            log.info("用户已登录,id为：{}",request.getSession().getAttribute("employee"));
            filterChain.doFilter(request,response);
            return;
        }

        //5.如果未登录, 则返回未登录结果
        log.info("用户未登录");
        response.getWriter().write(JSON.toJSONString(R.error("NOTLOGIN")));
        return;
    }

    private Boolean check(String uri,String[] uris){
        for (String url : uris) {
            boolean match = antPathMatcher.match(url, uri);
            if(match){
                return true;
            }
        }
        return false;
    }
}
